Field of the Disclosure
The present disclosure relates to a process for preparing treated inorganic core particles, typically titanium dioxide particles, and in particular to the preparation of treated inorganic oxide core particles, typically titanium dioxide particles, having improved dispersability.
Background of the Disclosure
Titanium dioxide particles such as pigment and nanoparticles are prepared using either the chloride process or the sulfate process. In the preparation of titanium dioxide pigments by the vapor phase chloride process, titanium tetrachloride, TiCl4, is reacted with an oxygen containing gas at temperatures ranging from about 900° C. to about 1600° C., the resulting hot gaseous suspension of TiO2 particles and free chlorine is discharged from the reactor and must be quickly cooled below about 600° C., for example, by passing it through a conduit, i.e., flue, where growth of the titanium dioxide pigment particles and agglomeration of said particles takes place.
It is known to add various substances, such as silicon compounds and aluminum compounds, to the reactants in order to improve hiding power and durability of the final product. Aluminum trichloride added during the process has been found to increase rutile in the final product, and silicon tetrachloride that becomes silica in the final product has been found to improve carbon black undertone (CBU), particle size and pigment abrasion. However the treatments added and the process used for the addition of these treatments result in treated titanium dioxide particles that do not disperse well.
A need exists for a efficient approach for adding elements to an inorganic core particle, typically a pyrogenically prepared metal oxide particle, and more particularly a titanium dioxide particle, to form a treated inorganic core particle having improved dispersability.